Recently, in the art of telephony, 2-wire copper telephone connections have been utilized for communicating two simultaneous channels, such as both digital data and analog voice signals. For example, a high speed digital subscriber line (DSL) channel (e.g., ADSL, SDSL, RADSL, VADSL, etc.) and a plain old telephone system (POTS) channel can be established over a single physical 2-wire connection. The signals are typically separated in frequency. The POTS channel usually exhibits a frequency spectrum of about 0 KHz to about 4 KHz, whereas the ADSL channel exhibits a frequency spectrum of about 20 KHz to about 500 KHz.
A POTS splitter is utilized to decouple the channels. A POTS splitter is typically a passive or active one-to-two port device. It often includes a low pass filter to minimize high frequency transients produced by on-hook/off-hook transitions so as to prevent tainting or slowing of the high speed data on the DSL channel. Also, it is usually configured to provide a high impedance to the telephone line in the ADSL frequency band in order to prevent ADSL power from being imparted on the POTS communications device that is connected to the line. Because of the foregoing requisite functionality, POTS splitters are usually expensive devices and are oftentimes installed on a physical wall of a premises, such as on an outside wall of a building. Furthermore, generally, POTS splitters require installation by a skilled telephone company worker, not the premises owner, resulting in undesirable installation time, labor, and expense.
The specification of POTS splitters has been the subject of several industry standards bodies. For example, see American National Standards Institute, ANSI T1.413-1995, Sections 8 and 10, regarding ADSL/POTS splitters. Moreover, as an example of a possible implementation of a POTS splitter, see J. Cook, P. Sheppard, "ADSL and VADSL Splitter Design and Telephony Performance," IEEE Journal on Selected Areas in Communications, December 1995.
A heretofore unaddressed need exist in the industry for an improved system and method for more efficiently and inexpensively implementing POTS splitters, (e.g., a distributed POTS filter) that permit the passage to the telephone of telephone company special signals, such as caller ID.